Recovery and use of olefins and hydrogen sulfide in gases



c. s. KELLEY RECOVERY AND USE OF OLEFINS AND HYDROGEN SULFIDE IN GASES Filed Dec. 27, 1954 Nov. 18, 1958 United States Patent RECGVERY AND' USE OF OLEFINSAND HY DRDGEN SULFIDEV IN `(SVASES,

Carl S. Kelley, Bartlesville, klal, assigner to Phiiiips Petroleum Company, a corporation of Delaware Application December 27, 1954, Serial No. 477,779

22 Claims. (Cl. 260-677) mercaptans, recovering low-boiling mercaptans from thec mercaptan conversion efuent and converting said mer- `captans to substantially pure olefins and/or alkylating at Y least one of said low-boilingpmercaptans with alowfboiling. isoparaflin. In another aspect of the invention it relates to the conversion of olefins to mercaptans employinga.

bauxite catalyst. In still another. aspect of the invention, it relates to the alkylation of, an isoparatlin with'a low- ICC n. if..

hydrogen sulfide is recovered and separated from said gases and passed by Way of conduit 12 to conduit 3 for reuse or. to storage. The hydrogen sulfide-.free gases from recovery unit 11 are removed for fuelvgas or other utilities by way of conduit 13. Enriched absorber oil from absorber 7` passes by way of conduit 15 to stripper fractionator 16 wherein fractionation and stripping operations are effected. Light' gases are removed overhead by way boiling alkyl mercaptan toproduce-an alk-ylatef'and hydro gen sulfide.

Other aspects, objects and the several advantages of the invention are .apparent from this disclosure/the drawing, and the appended claims.

According to this invention, there is provided a process for the recovery from gasesl containing'the same', of lowboiling olefins, hydrogen sulfide, and an alkylate. Thus, according to the invention, there is' provided a process in which olens contained in a gas stream are converted tomercaptans, the mercaptans recovered, 21nd if desired,

fractionated, and. then decomposed to4 yield substantially pure olefins by separationof them.frontliydrogen,.sulfide.V

concomitantly formed in Whichtprocess at least a portion of at least one of the. mercaptans. obtained. canbe ema. ployed to alkylate aloW-boiling isoparaftin, all as more fully described hereinafter.

The drawing illustrates a specific modus. operandi ac- .I

to a full understanding of the combination of steps, or

individual steps, which are involved.

Referring tothe drawing, in the embodiment shown a refinery cracked gas containing hydrogen, hydrogen' sul fide, nitrogen, methane, ethane, propane, ethylene, propylene, and a trace of C4 hydrocarbons is fed by way of conduit 2 together with hydrogen sulfide from conduit 3' by Way of conduit 4 into reactor 5.

In reactor S, mercaptan-forming reactions. areV main.- tained-and according to the invention, bauxite ist employed as aV catalyst toadvantageously convert the olefinsand hydrogen sulfide to mercaptans in good yield without forming undesirably high proportions of by-products which* are to be' avoided. Effluent from the reactor is Passed by Way of conduit6'i'ntooil absorber 7` inv which a lean oil `fed by way ofV conduitsV removes from said reaction effluent, substantiallyall4 ofA themercaptans which have been formed inreactor 5; kOyerhead from absorber 7 comprises hydrogen sulfide, nitrogen, hydrogen, and

ofconduit 17 and'may'bepassed at least in part byv Way of conduit 18 to conduit 9 and then by way of conduit 10 to hydrogensulfide recovery unit 1I. Lean oily recovered asbottoms from stripper-fractionator 16 is passed by way of conduit 8 to absorber 7'. From stripper-tractionator 16 there are obtained two principal mercaptan streams, ethyl mercaptan by way'of. conduit 19,' and propyl mercaptan by Way'ofconduit 20. Ethyl `mercaptan is passed by way'ofl conduit 19'tomercapta'n decomposerV unit' 21. In thisi unit', the mercaptan isA decomposedV with the aid offbeat and a catalyst, rfor example, bauxite,whioh can be regenerated bauxite priorlyemployed in reactor 5', and therein decomposed to yield hydrogen sulfide and Vethylene 4vvhicharepassed-by wayofV conduit-Z2 into amine hydrogen sulfide recovery'unit 23 wherein, by conventional. means,ethyleneisrecovered-andremoved by Way v25 of conduit Z4 substantially free from.'hydrogen sulfide.

...Hydrogen.sulfideisremoved by wayof-conduit 25 to con- -duit\26 and removedtto `storage and/orL returend by way of 'conduit27 and conduit 3 to reacto-r 5.. Propyl mercaptan *ispassedv by Way'of'conduitilto mercaptan decomposer 30 whereinunder conditions, similar to` those prevailing in mercaptan decomposer 21, the propyl-mercaptan'fisy converted toa gas stream containingj hydrogen sulfide and propylene which are passed by way of conduit 31 toamine hydrogen sulfiderrecover-y unit 32 from which substantially pure propylene is recovered and passed? to storage by Way ofconduit 33" and'hydi'ogeny sulfide is recovered by Vway of.' conduit 34 and passedto conduit 2z7`and/or conduit 3.

Propyl mercaptanisremovedfrom conduit'Zl), by way of" conduit 411iV and therein isadmixedwith analkylation isobutane, introduced by way of conduit 42, and passed'` b y. way ofV conduit 43 toialkylationin-alkylator 44. A1-A kylationefiiuent isremovedi from 44.by.way of conduit 45.. and passed to hydrogen sulfide separator unit 46. Alkyla-A ntionr eiiluent is"re'covere'd" and removedVv from the process` as a product by way of conduit47 and upon separationy fof acid and further treatment`n'ot shown, can beutilizedv asa component in motor fuel or for other'purposes as is` fwell-known in the art; Hydrogen sulfideV is removed.

from-separator 46-V by way of conduitY 48 and passed by way of, conduit 3'4'into conduit 3 and/orcondiit"27 A,

smallrproportion of propane resulting fromtthe-alk-ylat-ion reaction is removed'by way of conduit46".

Ethyl mercaptan ist also removed from conduit" 19 by jway of conduit.40.',.admixed Witnallcylation catalyst, in

this embodiment; hydrofiuor-ic acid or'sulfuricacid, introduced byway of conduit 41 and Y withY low-*boilingisd-v paraliin, in this embodiment, isobutane; introduced by way of conduit 4,2I andY passed by way of` conduit 43 to alkylationY in allylator 44fromr which anV alkylation effluent is removed by way of conduit 45 and'y passed to' hydrogensulfide-,separator unit' 4ST Alkylation-ei'uentlis-reco'veredj and removed from" the process-as lproduct by way of conduit 4'7, and upon separation of*- acid and further treatment,.not.sliown, can be utilized as a component in motor fuel orrfor, other purposes as is1 well known in the art. WI-,Iydrogen sulfide Yis removed from separator'46lby wayf'of conduit 48"" and Yis passed' into conduit 3 and conduit 27,., A propane: stream is 3 4 removed from separator 46 via 46". (This resulted (c) Catalyst--bauxite from the alkylation reaction.) (d) Regeneration-burn oft' sulfur and carbon with The compositions of streams shown on the drawing steam air mixture at 700-1100 F. are, of course, illustrative of theinvention and are not 2. MERCAPTAN DECOMPOSITION (21 AND 30) intended to be limiting in the sense that the invention is perforrnable only with the specific compositions set (b) Pressure s i a 200 forth. However, the reader Will have noted especially (C) Re enert?On tem air mixture at 7004100., F that the speciic combination of steps provides a highly g economical manner of utilizing the various streams which 3- PROPYL MERCAPTAN LIQUID PHASE (ONLY) are not only intermediates, in the, sense that they are ALKYLATION (44) not necessarily recovered as products of the process but (a) HF catalyst:

also, in the overall, for obtainin thoseY streams which (l) Temp' o F" 70'110 are removed as products of thegprocess. V(2) 4.0 to 1.0 up to 10.0 to 1.0 mol ratio of isov Table I shows the percentage composition and the butane to propyl mercaptan quantities flowing in the respective conduits of the sys- (3) Catalysttem described. The conditions of operation are shown 8579592 HF in Table II. These conditions are the now preferred 0'5"2'5% H2O conditions and one skilled in the art will ybe able to 25100% polymer 011 farmed m reaction vary, modify or extend the said conditions, where pos- 2'0-50% butane sible to do so, upon a study of this specication, draw- (4) The makeup acid is 99'i`% HF ing and the claims and the selection of a specific de- (b) H2504 catalyst:

sired operation to be accomplished. (l) Temp. F., 20-70 TABLE I Conduit 2 3 4 6 9 v1:5" 17 and 1s 12 13 1o Mols Mols Mols Mols Mols Mols Mols Mols Mols Mols Per- #/hr. Per- #/hr. Per- #/hr. Per- #/hr. `Per #Ihn Per- #/hr. Per- #/hr. Per- #/hr. Per- #Ihn Per- #/hr. cent cent cent cent cent cent cent cent cent M cent Component:

' CO 1.7 2.3 27 2.4 27 2.7 1.0 7.7 6.5 77 7.0 77 7.6 8.6 42. 5 35. 8 425 38. G 425 42. 3 47. 6 25.5 21.5 255 23.1 255 25.4 28.5 6. 0 5. 0 60 0. 9 l0 1. 0 l. 1 8.6 7.2 86 7.8 86 8.5 f 9.6 4.0 3.4 40 0.5 5 0.3 .1 0.3 1. 8 1. 5 18 1. 6 18 0.9 3 2. 3 2. 2 16. 8 200 10. 4 115 11. 2 1 0. 1

3 2 36 0 35 Isobutane.. A lkylate Et.

Total 100.0 1,000 100.0 188 100.0 1,188 100.0 1,103 100.0 1,006 100.0 97 100.0 13 100.0 104 100.0 895 100.0 49

Conduit 20 Y 42 47 4e 4s or 34"* sa 24 47' 25 or 48' 42' Mols Mols Mols Mols Mols Mols Mols Mols Mols Mols Per- #[hr. Per- #Ihn Per- #/hr. Per- #/hr. Per- #/hr. Per- #/hr. Per- #[hr. Per- #Ihn Per- #/hr. Per- #[hr. cent cent cent cent; cent cent cent cent cent cent Component:

Isobutane- Alkylate Eli Total Less absorber oli. Figures are for either alkylatlon or oleu manufacture.

It will be noted that the data of Table I are for either (2) 5.0 to 1-.0 up to 10.0 to 1.0 mol ratio of isoolen production or alkylation. When both operations butane to propyl mercaptan are simultaneously conducted the streams will, of course, (3) Catalyst--8Z-94% HZSO.,l be reduced in proportion to the split of the mercaptan 4 ETHYL MERCAPTA LIQUID PHASE (ONLY) Stream' ALKYLATION (44') TABLE n V (a) HF catalyst:

Operating conditions gm- 10?-11420 t 1 0 1 f f o upo o mo raioolso- 1. MERCAPTAN FORMIAG REACTION (5) y butane to ethyl mercaptan I (a) Temp., F.-150300 l(3) VCatalyst S23-95% HF and trace of BF3 may be (b) Pressure, p.s. i. g.100400 75 added (b) HzSOgcatalyst:

(1)' Temp., 40"-9'0 (2)". 6.0 to 10"up to` 101010 liO mol ratio of jisobutane toethyl .mercaptan (3) Catalyst-82494 HSO4 Theuse of bauxiteinvthe: mercaptan-forming reaction leading. tothe reacting outfrom the feed stream of ethylene, and propylene, by way of conversion to mercaptans, andI then recovering; said gases-. as described hereim. is. considered to\ be. a: particularly advantageous feature-ofthe` present invention.: Bau'xite is readily and relatively cheaplyy available'and operative over a wide range of; temperatures. However, silica-alumina synthetic catalyst, and silica-basedrphosphate.salt catalysts can` alsombeemployed. It is'fpossiblealso to employ halogen activated. bauxite; or silica-alumina catalysts. Certain: mixtures. of." the fregoingg. catalysts can be prepared'. and .proportioned to lpermit a' highlyV directedor selective. operation in; the. mercaptan-formingf,.steprv in reactor- 5.

The absorber oil, which: is: employed?. acoordingato :the inventiortrist one which possesses.v the characteristics-re.- quired. for" the absorption'. of: mercaptarns and can heza mineral seal oil;suchasnowfemployedin oiliabsorption processesknown to lthezart;

The hydrogen sulfidereoovery units as. illustrated by 11, 23 and 32 can be conventional ethanolan'nezre.- covery unitsirwhich .are alsowellknown .tothe-:art for the separation. of hydrogen sulfide. fromhydrocarbons. The

conditions of'operation' for'such units'are knoWninthe arti Reasonable variation' and modification?. as possible within the .scoperof' the foregoing disclosure, the'z drawing, andthe appended claims tothe. invention, the es.- sence of which isithat' conversion of 'olefins'to mercaptans employing bauxite asf a. catalyst-r and recovery of substantially pure-oletins; forexample, ethylene;.and alkylation of at'least onemercaptan, formed. in the process, for' example, propylm'ercaptan, with a1lowboiling-..isoparaffin, all substantially as set forth and describedhere.- in have been provided and that a unitary modus operandi for the recoveryjfrorn'aC stream of'crack'ed gases, or similar gases, of' hydrogen sulfide,- pureifloW-bloiling olefins, such as ethylene and propylene,and an alkylate produced' by way of' a mercaptan has also been provided, the..combinations of'steps in the unitary process being efiectuated substantially as described herein.

I claim:

l; Aprocess for the production of`a.high quality and concentration. ethylene gas andl a propylene. alkylate, from a. cracked4 hydrocarbon gas. containing ethylene, propylene, hydrogen sulfide, and 'other gases, which comprises adniixing'.- with'. said `cracked-v hydrocarbon gases hydrogen' sulfide obtained-ashereinafter. stated and. reacting the admixture .thus :obtained overfa bauxite catalyst under conditions and in a manner so as to produceA an eiuentcontaining ethyl mercaptan and -propyl mercaptan, passing, saidfefiiuent to'an oil absorptionzone andtherein absorbing into an absorption oil mercaptans and heavier materials .presentin said effluent, obtainingffrom said.y absorption.. zoneA anoverhead comprising; hydrogen sulfide, light hydrocarbons, and other gases, treating said gases to recover hydrogen sulfide therefrom and recycling said hydrogen sulfide for admixture with said cracked hydrocarbon gases, fractionating the absorption oil containing said mercaptans to obtain therefrom ethyl mercaptan as a stream and propyl mercaptan as another stream and lean absorption oil as a still further stream, passing said ethyl mercaptan under `desulfurizing conditions into contact with a bauxite desulfurization catalyst so as to obtain an eiiiuent containing ethylene and hydrogen sulfide, separating said hydrogen sulfide from said ethylene and recycling said hydrogen sulfide for admixture with said cracked hydrocarbon gases, recovering ethylene substantially free from all other gases including hydrogen sulfide as a product of the process, admixingsaid'propyl'mercaptan with isobutane and under alkylting'conditions passing the propyl mercaptan-isobutane admixture thus obtained into contact With an alkylation cataylst, recovering from the alkylation efiiuent hydrogen sulfide andv recycling the same for admixture with said cracked hydrocarbon gases and also recovering from said alk-ylation eiiiuent a` propylene alkylate.

2. A process for the production oa propylene alkylate, from a cracked hydrocarbon gas'containing ethylene, propylene, hydrogen sulfide, and other; gases, which comprises reacting said gas in the presence of a bauxite catalyst under conditions andV` in a manner so asto produce an effluent containing propyl mercaptan, passing` saidefiiuent to an oil'a-bsorption zone andtherein absorb; ingfinto an absorption oil mercaptan and heavier materials present in saidefiiuent, obtaining from saidl absorption zone overhead comprising hydrogen sulfide; light hydrocarbons, and other' gases, fractionatingthe absorption oil containing said mercaptan to obtain therefrom propyl mercaptanas aV stream and lean absorption oil aslfa still'further-stream, adniixing said'propyl mercaptan with isobutane and, under alkylatingconditions, passing the propyl mercaptan-isobutane'admiXture thus obtained into Contact with an alkylation catalyst, recovering from the alkylation efiiuent hydrogen sulfide and a-propylene alkylate. p

3. A processl` according to claim 2 wherein therecoveredVV hydrogen sulfide is'admixed with said cracked hydrocarbon gasas at leasta portion of the hydrogen sul'de used to produce `the propyl mercaptan.

4. A process for the production of a propylene alkylate from a gas containing ethylene,` propylene, hydrogen sulfide, and other gases, which'cornprises contacting said gas under mercaptan-forming conditions with a catalyst so asto produce an efliuent containing propyl mercaptan, separating from said efiiuenta propyl mercaptan stream, admiring said propyl mercaptan stream with a lowboiling isoparatiin and underalkylating conditions, passing the propyl mercaptan-loW-'boiiing isoparain admixture, thus obtained, into contactv with an` alkylation catalyst and recovering from the alkylation efiiuent hydrogen sulfide and avpropylenefalkylate.

5; A process accordingv tofclaim 4v wherein said lowboiling isoparafiin is isobutan'e.

6. Thel recovery of ethylene fromV av gas containing it together With other gases which comprises at a` temperature in the rangeu 15G-300"-` Fi passing said gas together with'hydi-ogensulfideintocontact with a bauxite catalyst to forman ethyl'mercaptan containing effluent, recovering ethyl mercaptan'from said efiiuent, decomposingl mercaptan to ethylene and hydrogen' sulfide and separating. ethylene and'h'ydrogen sulfideint'o` separate streams.

7. The-separation of low-boilingolefins fromfa cracked hydrocarbon gasf containing the'same which comprises admixingwith saidr ga'shydrogen sulfide', contacting the admixture` thusobtained under mercaptan-forming" conditions andv at a temperature in the range150-300 F. with a bauxite-catalystfso as to obtainvmercaptans-from saidzolefins; separating said` mercaptans from the catalyst efiiuent, decomposing. said rnercaptanslto olefins andi hydrogen sulfide, and separating the sameinto'a hydrogen sulfide.` stream. and. an'. olefin-containing stream; A

8; A.proc'ess:for the production oflazhighfquality-and concentration ethylene gas from a cracked hydrocarbon gas containing ethylene, propylene, hydrogen sulfide, and other gases which comprises reacting said gas in the presence of a bauxite catalyst under conditions and in a manner so as to produce an effluent containing ethyl mercaptan, passing said efiiuent to an oil absorption zone and therein absorbing into an absorption oil mercaptan and heavier materials present in said etiiuent, obtaining from said absorption zone an overhead comprising hydrogen sulfide, light hydrocarbons, and other gases, fractionating the absorption oil containing said mercaptan to obtain therefrom ethyl mercaptan as a stream and lean mercaptan under desulfurizing conditions into Vcontact with a bauxite desulfurization catalyst so as to obtain an eluent containing ethylene and hydrogen sulfide, separating said hydrogen sulfide from said ethylene and recovering ethylene substantially free from all other gases, including hydrogen sulfide, as a product of the process.

9. A process according to claim 8 wherein the hydrogen sulfide is admixed with said cracked hydrocarbon gas as at least a portion of the hydrogen sulde which is reacted to produce the ethyl mercaptan.

10. A process for the production of a high quality and concentration ethylene gas from a gas containing ethylene, propylene, hydrogen sulfide, and other gases, which comprises contacting said gas under mercaptan-forming conditions with a catalyst so as to produce an eluent containing ethyl mercaptan, separating from said efuent an ethyl mercaptan stream, passing said ethyl mercaptan stream under desulfurizing conditions into contact with a desulfurization catalyst so as to obtain an efuent containing ethylene and hydrogen sulfide, separating said hydrogen sulfide from said ethylene and recovering ethylene as a product of the process.

11. A process according to claim 10 wherein the catalyst in the mercaptan-forming step is bauxite.

12. A process according to claim 10 wherein the catalyst in the desulfurizationrstep is bauxite.

13. The alkylation of isobutane with propyl mercaptan at a temperature in the range -l40 F. in the presence of a catalyst selected from sulfuric acid and hydrouoric acid.

14. A process for the production of a low-boiling alkylate of isobutane which comprises, under alkylating conditions including a temperature in the range 70-110 F. and the presence of an HF alkylation catalyst, aikylating isobutane with propyl mercaptan.

15. A process for producing a low-boiling alkylate of isobutane which comprises, under alkylating'conditions including a temperature 'of 2070 F. and the presence of an H2804 alkylation catalyst, alkylating isobutane with propyl mercaptan.

16. A process for producing a low-boiling isobutane alkylate which comprises, under alkylating conditions including a temperature in the range of 10D-140 F. and the presence of an HF alkylation catalyst, alkylating isobutane with ethyl mercaptan.

17. A process for producing a low-boiling isobutane alkylate which comprises, under alkylating conditions including a temperature in the range of 40-90 F. and the presence of an H2804 alkylation catalyst, alkylating isolbutane with ethyl mercaptan.

18. A process for producing an alkylate product from a low-boiling isoparafiin and a low-boiling mercaptan which comprises bringing together into intimate contact said isoparaiiin and said mercaptan under conditions underl which an alkylation reaction between them occurs, said conditions including contact of said isoparafiin and said mercaptan with an alkylaton catalyst at a temperature in the range 20140 F., for a time sufficient to obtain a desired amount of an alkylate product and then recovering said alkylate product.

19. A process for producing an alkylate product from isobutane and propyl mercaptan which comprises bringing together into intimate contact said isoparain and ysaid mercaptan under conditions under which an alkylation reaction'between them occursfsaid conditions including contact of said isoparatiin'and said'mercaptan with an alkylation catalyst at a temperature in the range 20-140" F., for a time sufiicient to obtain Va desired amount of an alkylate product and then recovering said alkylate product.

20. The reaction under alkylating conditions, including a temperature in the range 20-140" F. and the presence of an acid alkylati-on catalyst, of a low-boiling isoparafin and a low-boiling mercaptan. 211. The reaction according to claim 20 wherein the low-boiling isoparafiin is substantially isobutane and the low-boiling alkyl mercaptan is substantially propyl mercaptan and the acid alkylation'catalyst is selected from the group consisting of HF and H2804 alkylation catalysts, wherein when HF is the catalyst selected the temperature is in the range -110 F., the molar ratio of isobutane to propyl mercaptan is in the range 4-10z1, and the concentration ofthe catalyst is in the range -95 percent HF in the reactor during on stream operation, and wherein when the catalyst is H2804 the temperature is in the range 20-70 F., the molar ratio of isobutane to propyl mercaptan is in the range 5-10:1, and the catalyst has a concentration in the range 82-94 percent H2804.

22. A reaction according to claim 20 wherein the lowboiling isoparain is isobutane, the low boiling alkyl mercaptan is ethyl mercaptan, wherein the catalyst is selected from hydrofluoric and sulfuric acids, wherein when hydrofluoric acid is selected as the catalyst, the temperature is in the approximateV range of 10U-140 F., the molar ratio of isobutane to ethyl mercaptan is 5-1421, and the catalyst has a concentration of 88-95 percent HF, and wherein when the catalyst is H280.,l the temperature is in the approximate range 40-90" F., the molar ratio of isobutane to ethyl mercaptan is 6-10z1, and the catalyst concentration is in the range 82-94 percent H2804.

References Cited in the tile of this patent UNITED STATES PATENTS 2,061,271 Buell et al. Oct. 8, 1935 2,375,724 Anderson et al. May 8, 1945 2,386,769 Badertscher et al. Oct. 16, 1945 2,387,162 Matuszak Oct. 16, 1945 2,387,224 Badertscher et al. Oct. 16, 1945 2,436,550 Brandon Feb. 24, 1948 2,441,493 Krug May 11, 1948 2,494,341 Lieber Jan. 10, 1950 OTHER REFERENCES Ellis: The Chemistry of Petroleum Derivatives, vol. II, page 470 (1937), pub. by Reinhold Publishing Corp., New York, N. Y.

The Chemistry of Petroleum Derivatives, Ellis, vol. Il, pages 462 and 478 (1937), Reinhold Publishing Corp., New York, N. Y.

Chemical Constituents of Petroleum, Sachanen, page 367 (1945), Reinhold Publishing Corp., New York, N. Y. 

4. A PROCESS FOR THE PRODUCTION OF A PROPYLENE ALKYLATE FROM A GAS ETHYLENE, PROPYLENE, HYDROGEN SULFIDE, AND OTHER GASES, WHICH COMPRISES CONTACTING SAID GAS UNDER MERCAPTAN-FORMING CONDITIONS WITH A CATALYST SO AS TO PRODUCE AN EFFLUENT CONTAINING PROPYL MERCAPTAN, SEPARATING FROM SAID EFFLUENT A PROPYL MERCAPTAN STREAM, ADMIXING SAID PROPYL MERCAPTAN STREAM WITH A LOWBOILING ISOPARAFFIN AND UNDER ALKYLATING CONDITIONS, PASSING THE PROPYL MERCAPTAN-LOW-BOILING ISOPARAFFIN ADMIXTURE, THUS OBTAINED, INTO CONTACT WITH AN ALKYLATION CATALYST AN RECOVERING FROM THE ALKYLATION EFFLUENT HYDROGEN SULFIDE AND A PROPYLENE ALKYLATE.
 7. THE SEPARATION OF LOW-BOILING OLEFINS FROM A CRACKED HYDROCARBON GAS CONTAINING THE SAME WHICH COMPRISES ADMIXING WITH SAID GAS HYDROGEN SULFIDE, CONTACTING THE ADMIXTURE THUS OBTAINED UNDER MERCAPTAN-FORMING CONDITIONS AND AT A TEMPERATURE IN THE RANGE 150-300*F. WITH A BAUXITE CATALYST SO AS TO OBTAIN MERCAPTANS FROM SAID OLEFINS, SEPARATING SAID MERCAPTANS FROM THE CATALYST EFFLUENT, DECOMPOSING SAID MERCAPTANS TO OLEFINS AND HYDROGEN SULFIDE, AND SEPARATING THE SAME INTO A HYDROGEN SULFIDE STREAM AND AN OLEFIN-CONTAINING STREAM.
 20. THE REACTION UNDER ALKYLATING CONDITIONS, INLCUDING A TEMPERATURE IN THE RANGE 20-140*F. AND THE PRESENCE OF AN ACID ALKYLATION CATALYST, OF A LOW-BOILING ISOPARAFFIN AND A LOW-BOILING MERCAPTAN. 